Can’t turn on serial number tracking

Can’t turn on serial number tracking

I cant turn on serial number tracking for certain items because they already have transactions attached to them.
we have over 100 items created that all have transactions attached to them, and we’d like to turn on serial number tracking.

these items are already on bills, and invoices. They are already attached to certain clients/projects, and inventory is being tracked for them.

is there no way to turn on serial number tracking for these items?